Abstract

ARAUJO, Nelson  and  GOTBERG, Estela. Extraction of acid metabolites during the analysis of catecholamines in rat brain tissue. Acta bioquím. clín. latinoam. [online]. 2010, vol.44, n.2, pp.179-187. ISSN 0325-2957.

The adsorptions of Dopamine (DA), Noradrenaline (NA), and Adrenaline (A) catecholamines were compared by using the batch equilibrium method, as well as those of the dihydroxyphenylacetic acid (Dopac) and indolacetic acid (5-HIAA) metabolites on the hydrophobic octadecyl (C₁₈), hydrophilic diol (C_Diol) and weak cation exchange (WCX) solid phases. On the WCX solid phase at pH 4.0, catecholamines adsorption of 78% and Dopac adsorption of 68% were observed. The adsorption isotherms of catecholamines on the for the WCX phase at pH 4.0 than dopamine, dopamine has greater affinity than Dopac, and this latter is coadsorbed over the adsorbed catecholamines on the WCX phase. A trial with organic solvents demonstrated that toluene selectively extracted Dopac and the coadsorbed 5-HIAA from a synthetic mix, while in a brain tissue specimen from experimental rats, Dopac and homovanilic acid (HVA) were extracted. These results served to propose an additional extraction step with organic solvents throughout the separation of acid metabolites during solid phase extraction (EFS) for the analysis of catecholamines.

Keywords : Solid phase extraction; Catecholamines; Homovanilic acid; Dihidroxyphenilacetic acid; Indolacetic acid; Weak cation exchange.

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